Drinking out of The Carton?

I have a husband and two boys, and I always catch them drinking out of the Tea, Coke, and Milk straight from the jug. If it was my hubby, I'd be okay, but my two boys don't have a 'clean mouth' really. They don't brush their teeth often, and before you say something like: Tell them to brush their teeth and stop drinking out of the carton! Beleive me I've tried. But I alwas catch them doing it again. I've reduced to being sanitary and only drinking tap water and canned cokes, which isn't the healthiest way to go. What do I do? I can't 'punish' them by grounding them for this, and I DONT my kids, especcially for something like this. What now?